Guilty Gear XX Λ Core (ギルティギア イグゼクス アクセントコア, Giruti Gia Iguzekusu Akusento Koa?, pronounced "Guilty Gear Igzex Accent Core") was released to Japanese arcades on December 20, 2006. A home console version on Sony'sPlayStation 2 was released on May 30, 2007 in Japan. A Wii version of this game was released on July 26, 2007, also in Japan, complete with support for the Classic Controller and Nintendo GameCube controller, along with a setup using both the Wii Remote and Nunchuk. Aksys Games released the PS2 version in America on September 11, 2007 and released the Wii version on October 16, 2007.

Λ Core features a new type of special move, the "Force Break," which consumes 25% of the Tension bar when used. Most characters have gained new special moves, and some have had existing specials (or powered-up versions of existing specials) converted into Force Break attacks. It also introduces moves that make opponents stick briefly to walls or slide across the floor of a stage. New additions also include "Slashback," a form of parrying with reduced block stun, and throw breaks.

In addition to its gameplay changes Λ Core features the first major aesthetic change for the series since the original release of Guilty Gear XX. All voices, including that of the announcer, have been re-recorded (or replaced with previously unused samples), sometimes by different actors. The playable characters artwork was also redone, and two new music tracks, Launch Out and Keep The Flag Flying, were added. Since this revision has been made to balance the game, two characters deemed illegal by tournament standards, Justice and Kliff, were removed from the game's playable roster.

Both versions of the game feature three gameplay modes per character, based on the Guilty Gear, Guilty Gear X, and Λ Core fighting systems.